I don't see LibreCMC (https://librecmc.org/) mentioned anywhere in this thread, so correct that.
Unlike Open WRT, LibreCMC is recognised by GNU to be a fully free Linux distribution, and you still get the time-honoured LuCi web administration interface.
LibreCMC runs on much fewer devices as OpenWRT, which can be a feature for those who are overwhelmed by the length of OpenWRT's list.
I know this will most probably be an unpopular opinion, but as someone who was born and raised in Central America, I have never understood why these countries are separate countries.